This invention relates to convertible sofas or sofa-beds which include a foldable bed frame which can be unfolded to a sleeping position. More particularly, the invention relates to a spring suspension for resiliently supporting the bed frame inside the sofa frame.
Sofa-beds are well known and have been available for many years. The advantage of a sofa-bed is that it can be used both as a sofa and as a bed. One of the disadvantages of a sofa-bed is that, when used as a sofa, it is not as comfortable as a conventional sofa. This is because a conventional sofa includes a resilient support for the seat cushions, such as an inner spring, which is designed specifically for providing seating comfort. On the other hand, a sofa-bed is used for both sitting and sleeping, and comfort in both positions is comprised in order to accommodate the dual function.
A sofa-bed conventionally includes a sofa frame and a foldable bed frame. The bed frame is folded inside of the sofa frame when the sofa-bed is used as a sofa, and the bed frame is unfolded so that it extends forwardly from the front of the sofa frame when the sofa-bed is used as a bed. When the sofa-bed is used as a sofa, the seat cushions are supported by the bed frame and by the bed mattress, and the sofa feels relatively stiff or firm compared to a regular sofa.